TY - JOUR
T1 - Bifunctional Electron-Transporting Agent for Red Colloidal Quantum Dot Light-Emitting Diodes
AU - Wang, Ya Kun
AU - Wan, Haoyue
AU - Xu, Jian
AU - Zhong, Yun
AU - Jung, Eui Dae
AU - Park, So Min
AU - Teale, Sam
AU - Imran, Muhammad
AU - Yu, You Jun
AU - Xia, Pan
AU - Won, Yu Ho
AU - Kim, Kwang Hee
AU - Lu, Zheng Hong
AU - Liao, Liang Sheng
AU - Hoogland, Sjoerd
AU - Sargent, Edward H.
N1 - Funding Information:
This work was supported by Samsung Electronics Co. (MRA 211815). We acknowledge financial support from the Natural Science Foundation of China (nos. 62205230, 51821002, 91733301), China Postdoctoral Science Foundation (2021TQ0230, 2021M690114), and the Collaborative Innovation Center of Suzhou Nano Science and Technology. Computations were performed on the Niagara supercomputer at the SciNet HPC Consortium. SciNet is funded by the Canada Foundation for Innovation, the Government of Ontario, and the University of Toronto.
Publisher Copyright:
© 2023 American Chemical Society.
PY - 2023/3/22
Y1 - 2023/3/22
N2 - Indium phosphide (InP) quantum dots have enabled light-emitting diodes (LEDs) that are heavy-metal-free, narrow in emission linewidth, and physically flexible. However, ZnO/ZnMgO, the electron-transporting layer (ETL) in high-performance red InP/ZnSe/ZnS LEDs, suffers from high defect densities, quenches luminescence when deposited on InP, and induces performance degradation that arises due to trap migration from the ETL to the InP emitting layer. We posited that the formation of Zn2+ traps on the outer ZnS shell, combined with sulfur and oxygen vacancy migration between ZnO/ZnMgO and InP, may account for this issue. We synthesized therefore a bifunctional ETL (CNT2T, 3′,3′″,3′″″-(1,3,5-triazine-2,4,6-triyl)tris(([1,1′-biphenyl]-3-carbonitrile)) designed to passivate Zn2+ traps locally and in situ and to prevent vacancy migration between layers: the backbone of the small molecule ETL contains a triazine electron-withdrawing unit to ensure sufficient electron mobility (6 × 10-4 cm2 V-1 s-1), and the star-shaped structure with multiple cyano groups provides effective passivation of the ZnS surface. We report as a result red InP LEDs having an EQE of 15% and a luminance of over 12,000 cd m-2; this represents a record among organic-ETL-based red InP LEDs.
AB - Indium phosphide (InP) quantum dots have enabled light-emitting diodes (LEDs) that are heavy-metal-free, narrow in emission linewidth, and physically flexible. However, ZnO/ZnMgO, the electron-transporting layer (ETL) in high-performance red InP/ZnSe/ZnS LEDs, suffers from high defect densities, quenches luminescence when deposited on InP, and induces performance degradation that arises due to trap migration from the ETL to the InP emitting layer. We posited that the formation of Zn2+ traps on the outer ZnS shell, combined with sulfur and oxygen vacancy migration between ZnO/ZnMgO and InP, may account for this issue. We synthesized therefore a bifunctional ETL (CNT2T, 3′,3′″,3′″″-(1,3,5-triazine-2,4,6-triyl)tris(([1,1′-biphenyl]-3-carbonitrile)) designed to passivate Zn2+ traps locally and in situ and to prevent vacancy migration between layers: the backbone of the small molecule ETL contains a triazine electron-withdrawing unit to ensure sufficient electron mobility (6 × 10-4 cm2 V-1 s-1), and the star-shaped structure with multiple cyano groups provides effective passivation of the ZnS surface. We report as a result red InP LEDs having an EQE of 15% and a luminance of over 12,000 cd m-2; this represents a record among organic-ETL-based red InP LEDs.
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U2 - 10.1021/jacs.2c13677
DO - 10.1021/jacs.2c13677
M3 - Article
C2 - 36897963
AN - SCOPUS:85149997700
SN - 0002-7863
VL - 145
SP - 6428
EP - 6433
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 11
ER -